It’s powerful stuff, and exactly the same goal as Canonical has with Ubuntu for Android and its attempted Ubuntu Edge smartphone, which failed to meet its Indiegogo crowdfunding goal last year. But Microsoft’s version is already real, unlike Ubuntu’s ambitions—with a few caveats. Continuum for Phones requires developers to embrace universal Windows apps to truly work, and the technology needs new hardware to function.

Microsoft just pulled off what Ubuntu couldn't. MS took a page from Apple and took someone else's idea and made it better. I'm sure they will do like Apple and patent it an sue Ubuntu if they are truly following Apples lead.

Windows 8 wanted to turns PCs into tablets and vice versa—and it
failed spectacularly. But with the help of universal Windows apps and a
page from Ubuntu Linux’s playbook, Microsoft aims to turn Windows 10
phones into full-blown PCs when they’re connected to PCs.

Microsoft’s universal apps use the same basic code base across devices and scale to fit the screen they’re being used on. Continuum is Microsoft's solution for shifting among various form factors.

Thus far, Continuum’s been discussed in terms of convertible devices—shifting to a touch-friendly tablet interface when you rip the keyboard off your Surface, and back to the desktop paradigm when the keyboard’s reattached. With Windows 10 phones, the devices will perform similarly to a traditional PC when they’re connected to an external monitor, along with a Bluetooth mouse and keyboard.

Any screen can be your PC (Responsive)
The first glimpse Microsoft provided of Continuum for Windows 10 phones during its Build keynote on Wednesday already looks spectacular. "With Continuum for phones, we believe any screen can be your PC,” Microsoft’s Joe Belfiore proudly exclaimed.

Even desktop-centric stuff will work just fine. Belfiore displayed seamless copying and pasting between mobile-centric apps, and yes, even the legendary ALT-TAB.